Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 22-02-2013, 12:42   #31
Moderator
 
sailorchic34's Avatar

Cruisers Forum Supporter

Join Date: Feb 2011
Location: SF Bay Area
Boat: Islander 34
Posts: 4,812
Re: Efficient battery driven air condition for Lagoon 450 catamaran

Quote:
Originally Posted by roetter View Post
I just found another Inverter Chiller from Frigomar. Looks like they are pretty new or does anybody know of one that has been around for a while?

Here is the PDF: http://www.frigomar.com/images/PDF/S...r_inverter.pdf
That's still a 230V system that inverts the A/C to DC to run a DC motor at variable speed. That AC to DC inverter will cost you about oh 3-6% in efficiency loss but makes up in part load performance. Minimum load is 900 watts. Max is 2.2KW with a single unit for a 3.5 ton unit.

But that's just the compressor load. On top of that you need to add chilled water pump(s), sea water pumps and fan motors on the fan coils. So you might need another 1 to 1.5 KW for the pumps and fans.

From a engineering standpoint your looking at about 1.1 KW per ton (12000 BTUs) of cooling or a bit more. That will be about the same with a water to water chiller or several water to air A/C units. On large systems, IE 1000 tons and up you can get the overall system efficiency's down to about .8kw per ton (and that's with a .55Kw/ton part load chiller, but for small systems its just not quite doable.
__________________

__________________
sailorchic34 is offline   Reply With Quote
Old 22-02-2013, 15:16   #32
Do… or do not
 
s/v Jedi's Avatar

Cruisers Forum Supporter

Join Date: Feb 2009
Location: in paradise
Boat: Sundeer 64
Posts: 9,198
Our NL genset is 6kW. The Victron Quattro can add 3kW to that with it's Power Assist feature so my maximum usable AC power is 9kW. Victron has a very good document about using smaller gensets and Power Assist; if you check that out, it'll change your plans
__________________

__________________
s/v Jedi is offline   Reply With Quote
Old 22-02-2013, 18:08   #33
Registered User

Join Date: Oct 2011
Location: Winter Bahamas - Summer BC
Boat: Lagoon 450, Bavaria Vision 40
Posts: 615
Quote:
Originally Posted by s/v Jedi View Post
Our NL genset is 6kW. The Victron Quattro can add 3kW to that with it's Power Assist feature so my maximum usable AC power is 9kW. Victron has a very good document about using smaller gensets and Power Assist; if you check that out, it'll change your plans
I had the Victron on my previous boat, mostly for the power assist feature. However, I am trying to find an energy efficient AC design to run off batteries at night for as long as possible. Also, I want a system that will easily handle just two cabins or sometimes four cabins without too much waste.
A variable frequency drive with a compressor that can handle it or an inverter chiller with a brushless DC compressor motor are my favourites so far.
__________________
roetter is offline   Reply With Quote
Old 22-02-2013, 18:37   #34
Senior Cruiser
 
Sailmonkey's Avatar

Cruisers Forum Supporter

Join Date: Sep 2009
Location: Houston
Boat: '76 Allied Seawind II, 32'
Posts: 5,764
Quote:
Originally Posted by roetter View Post

I had the Victron on my previous boat, mostly for the power assist feature. However, I am trying to find an energy efficient AC design to run off batteries at night for as long as possible. Also, I want a system that will easily handle just two cabins or sometimes four cabins without too much waste.
A variable frequency drive with a compressor that can handle it or an inverter chiller with a brushless DC compressor motor are my favourites so far.
I think you need to be thinking smaller. Why not cool only the cabin and not the whole boat?
__________________
Sailmonkey is offline   Reply With Quote
Old 23-02-2013, 12:37   #35
Registered User

Join Date: Oct 2011
Location: Winter Bahamas - Summer BC
Boat: Lagoon 450, Bavaria Vision 40
Posts: 615
Quote:
Originally Posted by Sailmonkey View Post

I think you need to be thinking smaller. Why not cool only the cabin and not the whole boat?
I think there was a misunderstanding in my answer. I just wanted to say that I am very familiar with the Victron Multi. I have programmed it in several ways and have run it with an small Honda inverter. Sometimes power/assist boost worked and sometimes the generator would kick out. To my best knowledge this would happen using the same loads. Typically in the morning, charging the empty batteries during overnight crossings with high autopilot loads and instruments all night and then someone starts to make a cappuccino while charging. The cappuccino maker would draw 250 A peak for a few seconds. I will get one again or maybe two in parallel, once I know the exact power requirements.

I have read the Victron generator-Multi test over and over. Lots of good information in it.

I am looking for a system that will easily adjust to the varying load requirements. Most of the times only two sleeping cabins have to be cooled. Occasionally three or four. I am not even planning to place an air handler in the salon. But I do not want 4 individual self contained units. In my opinion they take up too much space, make too much noise right under the beds, and are too inefficient. That is why I am thinking a chiller installed in the engine room with a variable speed drive compressor would be best suited.

Lagoon would install 4x8 and one 16k BTU self contained units. That makes 48k BTU. I am hoping for more around 24K BTU for the chiller.
__________________
roetter is offline   Reply With Quote
Old 24-02-2013, 04:50   #36
Registered User

Join Date: Jul 2011
Location: Australia NSW south coast
Posts: 633
Re: Efficient battery driven air condition for Lagoon 450 catamaran

Have you thought about DC powered compressors, they are popular with EV's and right trough to electric rail. Just a thought, maybe they don't go down to 12v systems though MasterFlux - Makers of AC and DC Variable Speed Compressors and Specialized Thermal Systems

T1 Terry
__________________
T1 Terry is offline   Reply With Quote
Old 24-02-2013, 11:57   #37
Registered User

Join Date: Oct 2011
Location: Winter Bahamas - Summer BC
Boat: Lagoon 450, Bavaria Vision 40
Posts: 615
Quote:
Originally Posted by T1 Terry View Post
Have you thought about DC powered compressors, they are popular with EV's and right trough to electric rail. Just a thought, maybe they don't go down to 12v systems though MasterFlux - Makers of AC and DC Variable Speed Compressors and Specialized Thermal Systems

T1 Terry
Great idea, but two problems.
1 they are air cooled only, not water.
2 the 12V versions only go to 6 KBTU

With today's semi conductor performance a brushless motor running at about 100V would be great. Model airplanes have speed controllers for brushless motors that process 30 volts at over 100 A, are the size of a match box and cost $100.

I am not sure what the 'inverter chillers' use. Does anyone know?
__________________
roetter is offline   Reply With Quote
Old 24-02-2013, 18:09   #38
Registered User

Join Date: Jul 2011
Location: Australia NSW south coast
Posts: 633
Re: Efficient battery driven air condition for Lagoon 450 catamaran

Just trying to expand on an idea here, if there was a compressor for each cabin and a raw water heat exchanger as the condenser section, would that make a simplified system? If each cabin is independently cooled the energy use could be minimised and save trying to keep a cabin cool with no one in it.

T1 Terry
__________________
T1 Terry is offline   Reply With Quote
Old 24-02-2013, 19:17   #39
Registered User
 
ebaugh's Avatar

Join Date: Dec 2011
Location: On the boat
Boat: DeFever 44
Posts: 525
You can try this, but if you want more than an hour or so of air conditioning, you will be happier with a genset.

Years ago, I had a 30 foot monohull with 12 golf cart batteries engineered to give me one night of AC at anchor. It worked, and sort of fit my weekend Saturday night at Shell Key cruising I did at the time. Then I plugged in at home on Sunday to recharge. But it was too much weight for the boat and I would probably not do it again.

But for more than a single overnight, a genset is the way to go. Solar and wind won't keep up on a boat to power A/C, so ultimately diesel fuel or gasoline will be needed to return the energy. There are 4 losses, inefficiencies in AC power generation, turning AC to DC, turning DC back to AC, and battery efficiency. Lithium iron battery chemistry helps, but I don't think solves the problem. Any battery solution has multiple losses, a genset only one. And all of the stuff to even attempt this is costly.

There are ways to make generators quiet, and this is really where the most bang for the buck is today. And you will end up using less fuel too.
__________________
ebaugh is offline   Reply With Quote
Old 24-02-2013, 23:48   #40
Registered User

Join Date: Oct 2011
Location: Winter Bahamas - Summer BC
Boat: Lagoon 450, Bavaria Vision 40
Posts: 615
Quote:
Originally Posted by ebaugh View Post
You can try this, but if you want more than an hour or so of air conditioning, you will be happier with a genset.

Years ago, I had a 30 foot monohull with 12 golf cart batteries engineered to give me one night of AC at anchor. It worked, and sort of fit my weekend Saturday night at Shell Key cruising I did at the time. Then I plugged in at home on Sunday to recharge. But it was too much weight for the boat and I would probably not do it again.

But for more than a single overnight, a genset is the way to go. Solar and wind won't keep up on a boat to power A/C, so ultimately diesel fuel or gasoline will be needed to return the energy. There are 4 losses, inefficiencies in AC power generation, turning AC to DC, turning DC back to AC, and battery efficiency. Lithium iron battery chemistry helps, but I don't think solves the problem. Any battery solution has multiple losses, a genset only one. And all of the stuff to even attempt this is costly.

There are ways to make generators quiet, and this is really where the most bang for the buck is today. And you will end up using less fuel too.
Thanks. Some good thoughts. I hear what you are saying.

On my previous boat I did not plug in or ran a generator from 2012 May until end of September in the Med. All power came from solar stored in the stock awful lead acid batteries. Those were 840Ahs of Exide. The solar usually filled them to 100% until the days got too short and cloudy. But then I would not need AC in winter. I could only use the batteries down to about 65% SOC, as below that the voltage would drop too much with 250A short time peak draw. (Electric winches or coffee maker). The inverter would complain of low voltage and the chart plotter would reboot. That means I had less than 300 usable Ah. The LFP batteries are much lighter than the golf cart ones you used back then.

The main consumption was from the fridges and the water maker ( run without an generator, which I was told could not be done, yet worked perfectly).

By the way, I have 6 golf cart batteries on my mono. No AC required were I sail her but a diesel heater.

I am now planning to have 50% more solar and have at least double the usable battery capacity.

Of the 200 plus days we stayed on the boat last year we would have used the air conditioning on a maximum of 20 days. That is 10 % of the days. For that I don't want to lug around a heavy generator.

I am still planning to have a generator, but a small one. I am planning to use the generator during the cool down phase and then I want to be able to run the AC maybe for another 2 hours at reduced power from batteries alone. The small generator will be supported by a Victron Quattro 5000.
__________________
roetter is offline   Reply With Quote
Old 25-02-2013, 00:03   #41
Registered User

Join Date: Nov 2011
Location: Fethiye Turkey
Boat: Lagoon 440
Posts: 3,164
Re: Efficient battery driven air condition for Lagoon 450 catamaran

Rolf are you doing the Bimini top in panels? I've seen your previous array and am thinking the Bimini is your plan?

Cheers good to see you on top again.

Frank
__________________
"Political correctness is a creeping sickness that knows no boundaries"
Lagoon4us is offline   Reply With Quote
Old 25-02-2013, 04:23   #42
Do… or do not
 
s/v Jedi's Avatar

Cruisers Forum Supporter

Join Date: Feb 2009
Location: in paradise
Boat: Sundeer 64
Posts: 9,198
When selecting a genset, have a good look at the weight of the units. I was in doubt over two models which turned out to be the same weight, so I went with the higher output of the two. Make sure to get an 1,800rpm one for 60Hz or 1,500rpm for 50Hz service, not the higher rpm brands (those have double the maintenance and repairs and half the service life, i.e. double trouble)
__________________
s/v Jedi is offline   Reply With Quote
Old 25-02-2013, 06:57   #43
Registered User
 
ebaugh's Avatar

Join Date: Dec 2011
Location: On the boat
Boat: DeFever 44
Posts: 525
Quote:
Originally Posted by roetter View Post
Of the 200 plus days we stayed on the boat last year we would have used the air conditioning on a maximum of 20 days. That is 10 % of the days. For that I don't want to lug around a heavy generator.

I am still planning to have a generator, but a small one. I am planning to use the generator during the cool down phase and then I want to be able to run the AC maybe for another 2 hours at reduced power from batteries alone. The small generator will be supported by a Victron Quattro 5000.
For discussion, assume you will meet all power needs except air conditioning with solar. Further, lets say all power except A/C requires 3 kWh a day. If you can end up with a surplus, it can be used for A/C. But it's going to take 6-8 kWh to run the AC for 3 hours in 4 cabins and 3-4 kWh for 2 cabins. This assumes at least 2 A/C systems or one of the fancy variable systems mentioned. For 20 days a year, it probably isn't cost effective to attempt to get this from solar, even if you can find the space which probably isn't there. As a result, the generator exists to power the air conditioning, and perhaps to cover deficits on cloudy days.

Once you make the decision to have a genset, it might as well be big enough to power the A/C directly. If its not, it will end up running more hours than the A/C to recharge unless you have a huge solar surplus, which is really hard to achieve. If you take a previous suggestion, which I second and get a 1500-1800 RPM genset, it will likely power the air conditioning anyway. The weight savings are then not in a smaller genset, but in reducing the solar and inverter systems to handle say 2 kW peak loads, which probably covers all other needs. Then you save weight by installing fewer batteries, a 2 kW Victron etc.

There is more power per pound in a generator than in batteries, even Li ones if it takes a generator to return the energy.
__________________
ebaugh is offline   Reply With Quote
Old 25-02-2013, 10:04   #44
Registered User

Join Date: Oct 2011
Location: Winter Bahamas - Summer BC
Boat: Lagoon 450, Bavaria Vision 40
Posts: 615
Quote:
Originally Posted by Lagoon4us View Post
Rolf are you doing the Bimini top in panels? I've seen your previous array and am thinking the Bimini is your plan?

Cheers good to see you on top again.

Frank
Hi Frank

Well, this is part of the therapy.

I have thought about using the Bimini top, but decided against it for now. Too easy to catch a line if you use framed panels. Flex panels are just too expensive for a lot of power. I would only do flexible panels to supplement some extra power. Also if the boom drops down to the Bimini ( which we managed to do a few times) the panels are toast. Our previous panels cost 1000 Euros for 950W. That was a really good price. The total install was about 2000 Euro ($2700) including Outback and the frame, which was really light.

I had 5 x 190 Kyocera extending the cockpit roof. Now I am planning 6 x 245 Kyocera in the same location. They will be 450 mm wider on each side, so a little wider than the cockpit roof and a little longer than the previous ones. I like the longer part, as it gives even more shade and rain protection. I am going for six panels so I can do them in 3s-2p configuration to stay below the max voltage for the Outback. As per specs they will be too much for the Outback (max 1250) vs 1140 installed, but I have never seen my previous system come close to rated performance. You would need the sun directly overhead or the panels directly aimed at the sun and a cool day. I used the panels just in the flat position until winter came and we did not get enough charge.
__________________
roetter is offline   Reply With Quote
Old 25-02-2013, 10:11   #45
Registered User

Join Date: Oct 2011
Location: Winter Bahamas - Summer BC
Boat: Lagoon 450, Bavaria Vision 40
Posts: 615
Quote:
Originally Posted by ebaugh View Post

For discussion, assume you will meet all power needs except air conditioning with solar. Further, lets say all power except A/C requires 3 kWh a day. If you can end up with a surplus, it can be used for A/C. But it's going to take 6-8 kWh to run the AC for 3 hours in 4 cabins and 3-4 kWh for 2 cabins. This assumes at least 2 A/C systems or one of the fancy variable systems mentioned. For 20 days a year, it probably isn't cost effective to attempt to get this from solar, even if you can find the space which probably isn't there. As a result, the generator exists to power the air conditioning, and perhaps to cover deficits on cloudy days.

Once you make the decision to have a genset, it might as well be big enough to power the A/C directly. If its not, it will end up running more hours than the A/C to recharge unless you have a huge solar surplus, which is really hard to achieve. If you take a previous suggestion, which I second and get a 1500-1800 RPM genset, it will likely power the air conditioning anyway. The weight savings are then not in a smaller genset, but in reducing the solar and inverter systems to handle say 2 kW peak loads, which probably covers all other needs. Then you save weight by installing fewer batteries, a 2 kW Victron etc.

There is more power per pound in a generator than in batteries, even Li ones if it takes a generator to return the energy.
I know already from my previous system that I will have at least 50% more power than I use in the warm months. It is only then that I need AC. A large genset will take up too much valuable space.

I am doing this to show that it can be done. Kind of a research project.

I am still not getting enough feedback on the core of my question - energy efficient air conditioning. Most of the feed back is how to power something that is not energy efficient.

I guess I was hoping to find someone on CF from the industry share my dream and is willing to do some research on this with me.
__________________

__________________
roetter is offline   Reply With Quote
Reply

Tags
battery

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 14:04.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.